package org.steven.crm.app.api;

import org.apache.commons.lang3.StringUtils;
import org.steven.crm.core.cache.RedisCache;
import org.steven.crm.core.utils.RandomCodeGenerator;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

/**
 * 验证码图片生成工具
 */
public class RandomCodeImageServlet extends HttpServlet {
	// 验证图片的宽度
	private int width = 120;

	// 验证图片的高度
	private int height = 38;

	// 验证码字符个数
	private int codeCount = 4;

	private int x = 24;

	// 字体高度
	private int fontHeight = 30;

	private int codeY = 30;

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// 定义图像buffer
		BufferedImage buffImg = new BufferedImage(width, height,
				BufferedImage.TYPE_INT_RGB);
		Graphics2D g = buffImg.createGraphics();
		// 创建一个随机数生成器类
		Random random = new Random();
		// 将图像填充为白色
		g.setColor(Color.WHITE);
		g.fillRect(0, 0, width, height);
		// 创建字体，字体的大小应该根据图片的高度来定
		Font font = new Font("Fixedsys", Font.BOLD, fontHeight);

		// 设置字体
		g.setFont(font);

		// 画边框
		g.setColor(Color.black);
		g.drawRect(0, 0, width - 1, height - 1);
		// 随机产生20条干扰线，使图像中的认证码不易被其他程序探测到
		g.setColor(Color.black);
		for (int i = 0; i < 20; i++) {
			int x = random.nextInt(width);
			int y = random.nextInt(height);
			int x1 = random.nextInt(12);
			int y1 = random.nextInt(12);
			g.drawLine(x, y, x + x1, y + y1);

		}
		// randomCode用于保存随机产生的验证码，以便用户登录后进行验证
		String randomCode = null;
		String reqeustId = request.getParameter("requestId");
		if (StringUtils.isNotEmpty(reqeustId)) {
			randomCode = RedisCache.getRandomCode(reqeustId, false);
		} else {
			randomCode = RandomCodeGenerator.generateCodeString(4);
		}


		char[] randomChars = randomCode.toCharArray();
		for (int i = 0; i < randomChars.length; i++) {
			// 得到随机产生的验证码数字
			// 产生随机的颜色分量来构造颜色值，这样输出的每位数字的颜色值都将不同
			int red = random.nextInt(255);
			int green = random.nextInt(255);
			int blue = random.nextInt(255);

			// 用随机产生的颜色将验证码绘制到图像中
			g.setColor(new Color(red, green, blue));
			g.drawString(randomChars[i] + "", (int) ((i + 0.5) * x), codeY);
			// 将产生的四个随机数组合在一起。
		}

		// 禁止图像缓存
		response.setHeader("Paragma", "no-cache");
		response.setHeader("Cache-Control", "no-cache");
		response.setDateHeader("Expires", 0);

		response.setContentType("image/jpeg");
		// 将图像输出到servlet输出流中
		ServletOutputStream sos = response.getOutputStream();
		ImageIO.write(buffImg, "jpeg", sos);
		sos.close();
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doGet(request, response);
	}

}
